The present invention relates to stick-type deodorant compositions. More particularly it relates to improved gel-type deodorant sticks, and also to methods for treating or preventing malodor associated with human underarm perspiration.
There are three main types of such stick formulations: compressed powder sticks, gel sticks, and wax sticks. While each of these formulation types may have advantages in certain use situations, each also has disadvantages. For example, compressed powder sticks are often brittle and hard, and leave a cosmetically-unacceptable dust upon application. Wax-based formulations can also yield cosmetically-unacceptable products due to such factors such as hardness, greasiness, and stickiness. The opacity of such wax sticks, and the residue created in their use, may also be aesthetically undesirable.
Gel based sticks have several advantages over both compressed power and wax sticks such as leaving little or no residue or dust. Gel sticks also provide a vehicle which glides easily over the skin surface.
In general soap-based gel-based sticks contain sodium stearate along with relatively high levels of either propylene glycol or ethanol. References disclosing such soap-type gel sticks include U.S. Pat. No. 4,154,816 to Roehl et al., issued May 15, 1979; U.S. Pat. No. 4,226,889 to Yukas, issued Oct. 2, 1980; and U.S. Pat. No. 4,268,498 to Gedeon et al., issued May 19, 1981.
Such soap-based sticks which contain high levels of propylene glycol tend to be sticky both during and after application thereby impartively relatively poor cosmetics. Other soap-based sticks may contain high levels of ethanol which leads to skin irritation. High lvels of ethanol also leaads to shrinkage and also weight loss of the packaged deodorant gel stick due to the volatility of ethanol.
Many stick formulations have been described in the literature which attempt to maintain the desirable cosmetic and aesthetic attributes of gel sticks, while minimizing their disadvantages. For example, antiperspirant gel sticks, using dibenzaldehyde monosorbitol acetal (herein "DBMSA") as a gelling agent, are described in U.S. Pat. No. 4,154,816, Roehl, et al., issued May 15, 1979, U.S. Pat. No. 4,346,079, Roehl, issued Aug. 24, 1982, and U.S. Pat. No. 4,518,582, Schamper, et al., issued May 21, 1985. Deodorant sticks using DMBSA are described in Japanese Patent No. 50/52,007, published Apr. 8, 1975. Nevertheless, it has been found that such DBMSA sticks, while avoiding the use of soaps, may produce products with aesthetically unacceptable stickiness. The solid gel sticks of the present invention provide very stable deodorant gel stick compositions with good efficacy as well as excellent cosmetics and aesthetics which are further characterized by their ease of manufacture.
It is therefore an object of the present invention to provide deodorant gel sticks which have good deodorant efficacy as well as improved cosmetics. It is still a further object to provide optically clear or translucent gel sticks which are cosmetically acceptable. A still further object of the present invention is to provide gel sticks which are stable and easy to formulate and manufacture. A still further object is to provide gel sticks which are non-sticky. A still further object is to provide gel sticks which contain relatively low levels of ethanol and propylene glycol to minimize skin irritation, stinging and burning.
These and other objects of the present invention will become readily apparent from the detailed description which follows.
All percentages and ratios used herein are by weight unless otherwise specified.